I have some co.cc domain, my case is:
mydomain1.co.cc is free hosting hosting, so people can create xxx.mydomain1.co.cc
mydomain2.co.cc is just a blog
mydomain3.co.cc is being banned by google
mydomain2 and 3 are backlink to 1
Eventhough mydomain3.co.cc is being banned, mydomain1 is still good and doesn't affected.